Investigation Of Thermal Comfort Research Articles

Investigation of thermal comfort and preferred temperatures among rural elderly in Weihai, China: Considering metabolic rate effects

As the population ages, the thermal environment indoors for the elderly has garnered extensive attention. However, current research on thermal comfort for the elderly is not comprehensive, particularly for rural elderly individuals who experience unique thermal perceptions and adaptation behaviors due to physical changes. Moreover, metabolic rates, which are often overlooked in thermal comfort studies for the elderly, play a crucial role. A year-long survey of thermal comfort was conducted in the rural areas of Weihai, a coastal city in China's cold region, collecting 203 questionnaires. Three different values of metabolic rates (recommended values, estimated values, and values calculated using Basal Metabolic Rate and Physical Activity Ratio) were analyzed. The results demonstrate that the Basal Metabolic Rate and Physical Activity Ratio method provides predictions of thermal sensation that more closely align with actual thermal sensations. The adaptive coefficient of the aPMV model was found to be −0.38 in colder environments and 0.272 in warmer ones. Additionally, using PMV regression, TSV regression, and Griffiths' method, we calculated the local elderly's comfort temperatures to be 18.9 °C (15.43–22.57 °C), 19.3 °C (15.16–22.75 °C), and 21.63 °C (21.34–23.49 °C) respectively. This study introduces a straightforward method for calculating metabolic rates in elderly individuals, offering new insights for research on thermal comfort in the elderly and expanding the database for thermal comfort studies. It lays a foundation for future design and standardization of housing for rural elderly populations.

Ten questions concerning statistical data analysis in human-centric buildings research: A focus on thermal comfort investigations

Given the large amount of time we spend indoors, designing and operating buildings that are safe, comfortable, and conducive to productivity and well-being is essential. To achieve this goal, in the past decades, research has been conducted to investigate the influence of the indoor environment on occupants. Thermal comfort has been the subject of most investigations in this field. However, despite being a consolidated research topic since the 1920s, statistical practices for analysing thermal comfort data often rely on simplified premises, which may be due to several possible factors (e.g., limited computational capabilities and lack of training). Consequently, important aspects of data analysis are often absent or overlooked. Recent statistics and statistical software advances have provided more options for effectively modelling complex issues. However, properly using these tools requires a solid understanding of statistical analysis, increasing the risk of misuse in practice. This paper presents ten questions highlighting the most critical issues regarding statistical analysis for thermal comfort research and practice. The first four questions provide general perspectives concerning statistical data analysis, while the remaining ones address specific problems related to thermal comfort research, but that can extend to all human-centric research in the built environment. Additionally, the last five questions demonstrate the practical significance of analysis pitfalls (i.e., sampling variability, selection bias, variable selection, clustered/nested observations, and measurement error) through examples with synthetic data. This study provides insights into the current statistical ‘habits’ in thermal comfort research and, more importantly, help researchers better define and conduct their statistical analyses.

Investigation of Airflow Characteristics and Thermal Comfort in Indoor Squash Court

Investigation of Airflow Characteristics and Thermal Comfort in Indoor Squash Court

Thermal comfort investigation of membrane-assisted radiant cooling in outdoor settings

The global warming and urban heat island effect call for mitigation strategies for improving thermal environments in open urban spaces. Radiant cooling can remove heat from the human body via direct thermal radiation, thereby creating the possibility to provide active cooling for people in outdoor environments. While using a transparent membrane, convection energy lost to the ambient airflow can be minimized. However, current research on the thermal comfort of radiant cooling systems is restricted to indoor applications, while outdoor applications remain unclear. To address this need, the study investigated the effect of membrane-assisted asymmetric radiant cooling on people's thermal perception in outdoor environments. A radiant cooling facility in an outdoor setting was built, and its cooling effects were assessed by using 248 human subjects across hot and transitional seasons. It is found that the radiant cooling facility can lower the mean thermal sensation vote (MTSV) by 0.6 to 1.5 units. The degree of cooling depends both on the panel temperature and environmental conditions. At the panel surface temperature of 14.3°C, MTSV was at the neutral zone (-0.5 ≤ MTSV ≤ 0.5) with the environmental UTCI as high as 38.1°C, whereas the thermal sensation of the group without radiant cooling was rated warm to hot. Under this condition, the ambient UTCI scope of no heat stress can be extended by 10.1°C higher. The strongest local cooling sensation appeared in the back, with an average decrease of 1.33 units in MTSV, contributing to lowering the overall thermal sensation of the body. For the first time, it is demonstrated that membrane-assisted radiant cooling panels can effectively improve thermal comfort in open outdoor settings.

Investigation of Airflow Characteristics and Thermal Comfort in Indoor Squash Court

Investigation of Airflow Characteristics and Thermal Comfort in Indoor Squash Court

3D CFD simulation of room air temperature and velocity with ceiling fan and exhaust fan and the resulting thermal comfort

The integration of energy-efficient solutions remains an essential hurdle in the pursuit of sustainable and comfortable indoor settings. As building energy consumption continues to climb, there is an urgent need to implement methods that reduce environmental effects, and at the same time, maintain adequate thermal comfort for occupant well-being and productivity. Ceiling fans, a standard fixture in many indoor settings, have gained popularity for their ability to provide better air movement and temperature adjustment while using substantially less energy than standard HVAC systems. This work presents a 3D Computational Fluid Dynamics (CFD) investigation of thermal comfort that can be achieved with a ceiling fan and an exhaust fan. A 3D fan zone model available in ANSYS Fluent was used to model the ceiling fan, considering the ceiling fan as a solid disc. Numerical methodology has been validated by verifying the transient simulation results against the experimental data available in the literature. The work analyzes thermal comfort parameters - temperature and velocity - in a room with a typical ceiling fan or an exhaust fan available in India. The room temperature and velocity distribution are presented for different times of a day in summer for a warm and humid climatic zone in India. The results show that the thermal comfort obtained with the exhaust fan is better than that with the ceiling fan for the evening, night, and early morning.

Investigation of Thermal Comfort, Productivity and Lighting Conditions in Higher Education Buildings

Thermal comfort and lighting conditions are essential aspects of indoor environmental quality. They are considered to influence the productivity of room users. The paper presents the experimental test results of research conducted in the university educational building of Kielce University of Technology (Central Poland) using anonymous questionnaires and physical measurements of indoor air parameters with a high-precision microclimate meter. It covers the analysis of the subjective assessment of thermal sensations, acceptability and preference, as well as productivity, lighting and air quality in eleven rooms (both lecture rooms and classrooms). The study analyses the impact of the indoor environment (mostly air temperature and illuminance) on the subjective sensations of the respondents they expressed in the questionnaires. The experiments have enabled us to provide valuable insights into developing the proper indoor environmental conditions to maximise room users' comfort and productivity.

Investigation of indoor thermal comfort and energy demand in different locations along the sub-Himalayan belt - A simulation based study

The sub-Himalayan region extends over 2500 km, extending over several countries. Though the effects of climate change is widely anticipated in the diverse but fragile ecosystem of the Himalayas, very less research has been conducted on the indoor environment of the buildings in these regions. In this study, a pre-validated model of 3-storey concrete residential building was used to study the indoor performance and thermal comfort in the face of climate change in the 8 (eight) different hill towns (hill stations) located from west to the east. Rise in ambient and indoor conditions were evident as a part of climate change with colder locations being affected the most. The thermal comfort assessment using both the climate chamber based PMV model and adaptive models revealed the decrease in cold related discomfort and increase in hot related discomfort. On an overall, the indoor conditions improved in these cold locations. The indoor and outdoor thermal condition and thermal comfort plummeted significantly with latitude and elevation. The heating demand in the future climate reduced by about 50–70 % in warmer locations, while the cooling demand increased by as much as 1000–2000 % in cold locations, respectively. Additionally, it was seen that the thermal environment and comfort both declined more rapidly with elevation in the locations lying in the western Himalayas as compared to those in the eastern Himalayas.

An investigation of indoor thermal environments and thermal comfort in naturally ventilated educational buildings

Indoor thermal conditions are essential in educational buildings. The health and well-being of students can be affected by a poor thermal environment, which also has a clear impact on building energy consumption. In this context, the indoor thermal environment in naturally ventilated university classrooms is explored in this study during a complete academic year. A monitoring campaign and a questionnaire survey were conducted simultaneously in higher education buildings in Spain. A total of 2115 sets of data were collected. Thermal sensation prediction indices (predicted mean vote, extended predicted mean vote and adaptive predicted mean vote) were applied to evaluate student’s thermal perception and their prediction accuracy was assessed. Additionally, two machine-learning models, based on Artificial neural network (ANN) and random forest (RF) algorithms, were formulated to predict occupants’ thermal sensation. The obtained results evidenced that the proposed ANN and RF models outperform traditional indices. Finally, it is also proposed an adaptive thermal comfort model. The results obtained suggest that students have a greater adaptive capacity to changes in environmental conditions than suggested by the ASHRAE-55 adaptive model and that they preferred an environment with lower temperatures than those suggested by the EN-16798 adaptive model.

Thermal comfort investigation and management of public spaces of Clement Town, Dehradun, India

Thermal comfort investigation and management of public spaces of Clement Town, Dehradun, India

Investigation of indoor thermal comfort of heritage buildings in hot summer and cold winter zone of China: A case study

The heritage buildings of a country or region are frequently considered to be of value and significance to the current generation. This study investigates the winter indoor thermal comfort of heritage buildings in hot summer and cold winter zone of China. Field measurements and questionnaire surveys were used to conduct specific studies on the winter indoor thermal comfort of two typical traditional residential buildings (“Yinziwu” and “Diaojiaolou”) in the Yuan River basin heritage building area. The aim is to investigate the current status of building thermal comfort and provide a theoretical basis for promoting their sustainable development. The results show that 1) Indoor air temperatures in both types of buildings are significantly and positively correlated in winter, but both are below the human thermal comfort range. 2) Mean air temperatures measured in "Yinziwu" and "Diaojiaolou" are 8.8 °C and 9.4 °C, respectively, with neutral air temperatures of 11.1 °C and 13.8 °C. 3) Thermal sensation, thermal preference, and thermal comfort were significantly correlated in the two buildings, with ooccupants experiencing the coldest phase from 7:00–11:00 and the warmest phase from 15:00–19:00 daily. 4) "Yinziwu" occupants are more tolerant of the cold climate.

Investigation and optimization of outdoor thermal comfort in elementary school campuses: Example from a humid-hot area in China

The elementary school campus is the primary location where children both learn and live. The school environment significantly impacts children's health and well-being. While today's primary school campus designs generally adhere to regulations, they may still offer an unsafe thermal environment. To address this concern, we conducted a thermal sensory questionnaire in a representative outdoor space of an elementary school campus in Guangzhou, China. The thermal comfort of children was assessed using the Universal Thermal Climate Index (UTCI). Additionally, to enhance the thermal environment of current primary school campuses, we conducted a tree landscape preference survey. Based on children's thermal benchmarks and plant landscape preferences, a bioclimatic design for outdoor activity spaces on primary school campuses in humid-hot areas is proposed. The results show that: (1) Air temperature and mean radiant temperature are the main meteorological factors affecting children's thermal sensations in summer; (2) The outdoor neutral UTCI of male and female children is 25.0 and 22.8 °C, respectively, and the acceptable UTCI is 29.7 and 27.1 °C, respectively; (3) With respect to landscaping, children prefer large trees and evergreens planted in a plant community or singly. Their weighted preference scores were 3.10, 2.63, 2.27 and 1.89 respectively; and (4) Based on children's thermal benchmarks and plant landscape preferences, a tree-planting design strategy for primary school campuses in hot and humid regions is proposed. This study provides valuable advice for architects and landscape planners with respect to the design of elementary school campuses.

Empirical investigation of occupant-centric thermal comfort in hotel guestrooms

Given the importance of occupant satisfaction with thermal comfort in hotel accommodations, previous studies have assessed thermal comfort using either local or global standards. In a hotel catering to diverse guests, a single standard may constrain the formulation of an optimal strategy for improving occupant satisfaction. To address this challenge, this study empirically investigates occupant-centric thermal comfort in hotel guestrooms located in a hot and humid climatic region. To this end, a living-lab-based case study was conducted on a hotel guestroom in Hong Kong, wherein two types of thermal comfort improvement strategies were devised from both local and global perspectives. First, to improve thermal comfort in line with the local standard, it was determined that an ancillary fan coil unit (FCU) energy consumption of 6.0 kW h (approximately 34 % of the existing energy consumption) was required. Second, to improve thermal comfort in line with the global standard, an ancillary FCU energy consumption of 9.4 kW h (approximately 53 % of the existing energy consumption) was necessary. Consequently, in a hot and humid climatic region, the distribution of thermal comfort may vary depending on the type of guest (e.g., domestic or foreign), and ancillary cooling energy expenditure may be incurred to enhance a guest's thermal comfort. The proposed approach is expected to contribute to the creation of occupant-tailored thermal comfort by considering an individual's thermal acclimation to a specific climatic region from both local and global perspectives.

Investigation of Thermal Comfort for ANaturally Ventilated House: Correlation between Climatic Design Strategy and Thermal Data Analysis

One of the main factors contributing to climate change and global warming is architecture, which accountsfor about 50% of the country's greenhouse emissions due to construction and the energy needed to keep buildings operational. Sustainable architecture is believed to reduce emissions, andthisapproach has been practisedwithtraditional buildings. In Malaysia, a traditional Malay house (TMH) is one of thetraditional buildings, and it is initially naturally ventilated with occupant-controlled air ventilation to condition the space. Numerous experimental studies claimed that TMHhas demonstrated a good model for contemporary designers to understand climatic and environmental design, building systems, and design adaptability.One of the approaches is to practiseclimatic design strategies. However, there is a lack of study to determine if TMH is still relevant as a sustainable design that can adapt to current climate conditions. Thus, the study aims to investigate the adaptive indoor thermal comfort of a Negeri Sembilan Malay house in a hot-humid climate determinedby the correlation betweenclimatic design strategy and thermal data analysis. This study employed the Predictive Adaptivemodel by executing two stages of fieldwork: i) local climate background and ii) physical measurement (case study description and environmental data). The data were thenanalysed using the ACS of ASHRAE 55 and MS 2680:2017. The primary results revealed that 62% of the hourly indooroperative temperatureof the case study house waswithin 80 to 90 % of the acceptability limit. The optimal comfort hourly indooroperative temperaturewasbetween25.5 to 29.5 °C with a prevailing mean outdoor air temperaturebetween23 to 30 °C, which represents 90% of the acceptability limitrange. Moreover, the results also complied with the standards of ACS, where the average hourly indooroperative temperature was less than 31 °C,with a prevailing mean outdoor air temperatureless than32 °C, which wasan acceptable indoor state for occupants' comfort. The findingscompliedwith RMK 12 Theme 3, which aims to be a carbon-neutral country by practising sustainable architecture and construction. The design of naturally ventilated houses, such as Negeri Sembilan Malay houses in hot-humid climates, can be a model reference for modern housing design development.

Investigation of thermal comfort and preferred temperatures for healthcare staff in hospitals in Ningbo, China

Appropriate thermal comfort is crucial for healthcare staff to ensure a conducive working environment. Literature review indicates that staff have a much different thermal comfort requirement from patients and visitors, which has not received sufficient attention in current studies. This empirical study was conducted from December 2021 to November 2022 in dental treatment departments of four hospitals in Ningbo, China. A total of 333 questionnaires were collected and analysed to investigate the current thermal environment, the thermal sensation of healthcare staff, and the seasonal variation of the metabolic rate and clothing insulation. The adaptive coefficient of the adaptive predicted mean vote (aPMV) model for healthcare staff was −0.34 in cooler environments and 0.128 in warmer environments. The calculated thermoneutral temperatures, derived from PMV regression, TSV regression, and the Griffiths method, stood at 21.81 °C, 20.99 °C, and 22.54 °C, respectively. Correspondingly, the associated comfort temperature ranges in the case study healthcare buildings were 19.10–24.51 °C, 17.66–24.33 °C, and 22.24–22.84 °C. These parameters play a pivotal role in establishing precise thermal benchmarks and ensure optimal thermal experiences for healthcare staff investigated. The novelty of the research lies in thoroughly investigating the thermal comfort of healthcare staff, with the development of the adaptive models tailored to the climatic conditions of the Ningbo region and the specific characteristics of healthcare staff. Additionally, the research rigorously compares and validates these findings with established standards and previous studies in the field. The research indicated that the resulting comfort temperatures, while lower than established adaptive regulations, closely align with the recommended temperatures in the healthcare building design specifications.

Numerical investigation of indoor thermal comfort and air quality for an office equipped with corner impinging jet ventilation

ABSTRACT This study investigates the feasibility of using only corner impinging jet ventilation (CIJV) for heating and cooling a medium-sized office space with two occupants while maintaining adequate indoor thermal comfort and air quality compared to traditional mixing ventilation systems. This study examines what impact various outdoor temperatures, ranging from −15°C to 25°C, have on an office environment in terms of indoor thermal comfort and air quality. Three different workspace positions were evaluated. The results show that the CIJV system meets the ASHRAE thermal comfort standards for all three positions. In terms of indoor air quality, CIJV performs better than traditional mixing systems, with improved mean age of air and ACE values. This study concludes that CIJV can be used both close and far away from the supply inlets and still provide adequate indoor thermal comfort and air quality during both cooling and heating season.

Local climate zone mapping using remote sensing: a synergetic use of daytime multi-view Ziyuan-3 stereo imageries and Luojia-1 nighttime light data

ABSTRACT The local climate zone (LCZ) scheme has been widely utilized in regional climate modeling, urban planning, and thermal comfort investigations. However, existing LCZ classification methods face challenges in characterizing complex urban structures and human activities involving local climatic environments. In this study, we proposed a novel LCZ mapping method that fully uses space-borne multi-view and diurnal observations, i.e. daytime Ziyuan-3 stereo imageries (2.1 m) and Luojia-1 nighttime light (NTL) data (130 m). Firstly, we performed land cover classification using multiple machine learning methods (i.e. random forest (RF) and XGBoost algorithms) and various features (i.e. spectral, textural, multi-view features, 3D urban structure parameters (USPs), and NTL). In addition, we developed a set of new cumulative elevation indexes to improve building roughness assessments. The indexes can estimate building roughness directly from fused point clouds generated by both along- and across-track modes. Finally, based on the land cover and building roughness results, we extracted 2D and 3D USPs for different land covers and used multi-classifiers to perform LCZ mapping. The results for Beijing, China, show that our method yielded satisfactory accuracy for LCZ mapping, with an overall accuracy (OA) of 90.46%. The overall accuracy of land cover classification using 3D USPs generated from both along- and across-track modes increased by 4.66%, compared to that of using the single along-track mode. Additionally, the OA value of LCZ mapping using 2D and 3D USPs (88.18%) achieved a better result than using only 2D USPs (83.83%). The use of NTL data increased the classification accuracy of LCZs E (bare rock or paved) and F (bare soil or sand) by 6.54% and 3.94%, respectively. The refined LCZ classification achieved through this study will not only contribute to more accurate regional climate modeling but also provide valuable guidance for urban planning initiatives aimed at enhancing thermal comfort and overall livability in urban areas. Ultimately, this study paves the way for more comprehensive and effective strategies in addressing the challenges posed by urban microclimates.

Field investigation of thermal comfort with face masks in outdoor spaces in South China: A case study

After the outbreak of coronavirus disease 2019 (COVID-19), individuals have paid significant attention to protecting themselves indoors and outdoors by wearing masks. However, wearing masks can affect the exchange of heat and moisture between the body and the environment, which in turn affects the thermal comfort of the body and causes discomfort, leading people to wear them in an unscientific and standardized manner, affecting people's healthy lives. Thus, to analyze its effects on thermal comfort, outdoor parameter measurements and field surveys were conducted at Guangzhou University to investigate the thermal comfort of pedestrians wearing masks outdoors. In this study, the physiological equivalent temperature (PET) was chosen for thermal comfort evaluation. Based on the field survey, the neutral PET and preferred PET of the subjects with and without masks were determined. The results indicated that the neutral temperature of people wearing masks are slightly lower than that of people without masks, and people with masks need a lower ambient temperature to feel comfortable. Out of the total, wearing masks raised the heat sensation in the face more and caused discomfort to the face. In addition, the suitability of PET for the people with masks was initially evaluated.

Investigation of summertime thermal comfort at the residences of elderly people in the warm and humid climate of India

According to WHO (World Health Organization) data, people spend at least 80% of their lives indoors, with the percentage rising to 95% for older people with mobility impairments. Creating a thermally comfortable indoor environment is essential for improving users’ productivity and well-being, particularly for those who spend maximum time indoors, such as elderly people. India’s ageing population is increasing significantly; however, there is lack of studies in the field of thermal comfort for the elderly. The main aim of this paper is to determine the thermal comfort range of elderly people in residences of warm and humid climates during summers in India and to find out the adaptive actions opted by the elderly population to achieve thermal comfort. 740 responses were collected from elderly people through questionnaire surveys along with simultaneous field measurements during the summer. The linear regression analysis found the occupant’s comfort temperature of 30 °C and the comfort range was found to be 28.5 °C- 31.5 °C, which was narrower than the younger people’s thermal comfort studies at residences. The neutral temperature was higher for the male elderlies than the female elderlies, which was highly correlated with their clothing adjustments. The probit analysis revealed that 90% of the elderly felt comfortable when the operative temperature varied between 26.9 °C and 30.9 °C. Clothing adjustments and taking cold showers are the most preferred behavioural actions by the elderlies in summer, whereas changing the cooking time and tying up hair are the most preferred behavioural adaptations to overcome thermal discomfort for female elderlies.

Investigation of Thermal Comfort in the Intelligent Building in Winter Conditions

The paper analyses thermal sensations, preferences and acceptability as well as humidity sensations of students in the intelligent building "Energis" of the Kielce University of Technology (Poland). The tests were performed in 8 lecture rooms, during which the volunteers filled in the anonymous questionnaires (with 3 to 7 possible answers for each question) and – simultaneously – physical air parameters were measured with Testo 400 microclimate meter. The study aimed to determine if the intelligent building provides proper indoor environment conditions during the heating season and to assess the accuracy of the standard methodology for thermal comfort determination. Experimental analysis of thermal and humidity sensations revealed that a share of the respondents critically assessed the indoor environment: 17% regarding temperature and 30% regarding humidity. Moreover, the standard methodology for thermal comfort calculations proved overwhelmingly inaccurate compared to the experimental data (with the results for 6 rooms being beyond the 50% error range). Since smart buildings are still not very common in Central Europe, the experimental data obtained in the study can be valuable both from the scientific but also practical point of view – providing useful data for building engineers and designers.